High-sensitivity sensor based on surface plasmon resonance and heterodyne interferometry

Chien Ming Wu*, Zhi Cheng Jian, Shen Fen Joe, Liann Be Chang

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

88 Scopus citations


A common-path, heterodyne interferometric system for investigation of the phase variations under surface plasmon resonance (SPR) is presented. With the combination of SPR and total internal reflection (TIR), the system has the merits of avoiding direction change in the output light and increasing sensitivity. The system utilizes a pair of orthogonally linearly polarized beams with heterodyne frequency of 60 kHz as the light source. Because the two beams are perfectly collinear, the noises resulting from the ambient conditions are greatly reduced. Compared to reflectivity variation measurement, which is widely used in traditional SPR, the phase variation measurement using common-path, heterodyne techniques is approximately an order of magnitude higher in sensitivity and thus can be used as a high-sensitivity-demanded biosensor.

Original languageEnglish
Pages (from-to)133-136
Number of pages4
JournalSensors and Actuators, B: Chemical
Issue number1-2
StatePublished - 01 07 2003
Externally publishedYes


  • Interferometers
  • Phase measurement
  • Sensors
  • Surface plasmon resonance
  • Waveguides


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